They were best friends, both 18, college freshmen, co-workers. Inseparable since kindergarten, Jessica Rasdall and Laura Gorman loved to go out, loved to dance, to have fun. The good times might have lasted a lifetime, but for the tragedy that unfolded on a Florida highway early one February morning in 2006.

It started with a trip to a club. There were drinks, and a walk to the car, with Rasdall taking the wheel. Less than an hour later, Gorman was dead. And her best friend would be charged with killing her.

Watch the full story on "20/20" Friday at 10 p.m. ET.

On average, a drunken driver kills someone every 40 minutes in the United States. That's 36 deaths daily and more than 13,000 annually. The highway deaths are so frequent they can go unnoticed, until one hits close to home.

"My name is Jessica Rasdall, and on Feb. 25, 2006, I killed my best friend," Rasdall, now 22, tells a crowd of high school students packed into a football stadium under a brilliant blue Tampa, Fla., sky.

"Laura Ann Gorman died in the passenger seat of my car ..."

In the last three years, Rasdall has confessed her crime to more than 15,000 people, both young and old, in a speech that never varies, describing the minute details of that tragic night. At the end she plays a slideshow tribute to her dead friend, set to the song "Second Chances" by Michelle Branch.

"I wish I could take her place that night," Rasdall told Elizabeth Vargas of "20/20" in an interview before she went to prison. "I would give anything to have been the one in the passenger seat that night ... Absolutely. No questions asked. ... I would give anything to just bring her back."

Drunken Driving: A Cautionary Tale

Rasdall's story is a cautionary tale of love and loss, of overwhelming regret and remorse. Even as she tries to atone for what happened, she faces accusations of hypocrisy from the Gorman family, who say that her public speaking is merely an attempt to win leniency from the courts. She also has been accused of a pattern of dangerous behavior, of having mixed alcohol and driving in the past.

But most of all, there is the hard reality that she must wake up to each morning. Her best friend is gone, and she is to blame.

There is a sign along Interstate 275 in west central Florida -- near St. Petersburg, where the friends grew up -- in memory of Laura Gorman. It marks the spot where she died. Rasdall said she often visits the crash site and reflects on what might have been.

"It still almost [doesn't] seem real to me that a car accident ... that one night ... in the blink of an eye, everything changed," she said.

The two met in kindergarten. As they blossomed into young women, they dyed each other's hair, experimented with makeup. They even began working at the same restaurant, a local Hooters.

"We were complete opposites but so much alike," said Rasdall, who even now talks about her dead friend in the present tense. "I was the short one, she's the tall one. I was the brunette, she's the blond. You couldn't help but be happy and smile when you're with her."

On the night of Feb. 26, 2006, the two worked their usual shift at Hooters. They headed back to Laura's dorm at Eckerd College in St. Petersburg. And then they decided to go out dancing.

Drunken Driving: Inside the Club

With Rasdall driving, they headed to the outskirts of Tampa, to Ybor City, where historic cigar factories have become teeming bars and nightclubs. At the bar that night, women 18 or older got in for free, while men had to be at least 21 and pay to enter.

The girls hit the dance floor and then, Rasdall claims, a man working at the club waved them over to the bar.

"He asked, 'Are you girls 21? Because it doesn't matter,'" Rasdall said. "He got the bartender's attention, told her to order us a drink, and then he said, 'let's switch to shots -- they're quick, they're fast, no one will even see the cup in your hand, it's in and out.'

"It was a really weird feeling, almost like, well, this guy works here and he's saying it's OK, we're allowed to do this."

All of this is documented in photographs from a camera later found in the destroyed car. Best friends posing, dancing and drinking. Haunting images of life, just hours before death.

At 3 a.m., the two women finally left the club. Rasdall said they didn't think twice about getting in the car. With Rasdall at the wheel, the best friends began the 40-minute drive home.

And then, one mile from Laura's dorm, it happened. The car drove off Interstate 275 and down a hill, crashing into a broad tree. Both women were wearing seat belts.

Rasdall said the next thing she remembers, she woke up in the car on the side of the road.

"I didn't know where I was, who I had been with, I couldn't remember anything," she said. "I saw somebody was sitting in my passenger seat. The person's face was turned away from me. I shook her arm. And deep down I knew the person next to me was dead."

When paramedics arrived Rasdall was screaming and in pain. Rescuers using the Jaws of Life freed her and rushed her to the hospital.

A few miles away, Assistant State Attorney Rohom Khonsari was awakened by his cell phone. Minutes later, he arrived at what was now considered a crime scene. There had been a fatality, and DUI was suspected. Walking down from the highway, Khonsari remembers looking inside the vehicle. Laura Gorman, still in the passenger seat, had died of blunt force trauma to her head.

"My heart dropped," Khonsari told Vargas. "That's the first dead body I've ever seen. You instantly think she's young, she's got a family somewhere right now that doesn't know what just happened. It's a picture that's really hard to let go of." At the hospital, nurses cut off Rasdall's clothes and hooked her up to machines. A large gash crossed the side of her head and her left ear was hanging off.

As she was prepped for surgery, Rasdall heard a police officer talking to her mother. He described a purse that belonged to Gorman. Suddenly Rasdall realized who her passenger had been.

"I was screaming at the top of my lungs," she remembered. "'Not Laura! Why not me! Her parents are going to hate me!' And I was screaming, screaming 'I killed my best friend!'"

Drunken Driving: Victim's Family Blames Driver

It took 400 stitches to put Rasdall's head back together. A blood sample was turned over to law enforcement. Tests showed her blood alcohol content was nearly one-and-a-half times the legal limit, evidence that the crash was the result of DUI.

On the day Rasdall came home from the hospital, Gorman's body was placed in a mausoleum.

To this day, the two families, the Rasdalls and the Gormans, once friends, no longer speak.

"They had told us not to come to the funeral," Rasdall said. "I've sent cards, letters, flowers, saying how sorry I am. But they're not ready."

The victim's parents, Rod and Helen Gorman, declined repeated requests to comment for this story, but they did allow prosecutor Khonsari to speak on their behalf.

According to Khonsari, the Gormans were grief-stricken and numb after the accident. It was the second child the couple had lost, he said -- a son had died as a baby.

"They were a mess. And they continue to be angry today," Khonsari told Vargas.

One month after the accident, Rasdall was arrested and charged with DUI manslaughter. In accordance with the Gormans' wishes, prosecutors told the judge that they would seek the maximum sentence of 10 to 15 years in prison. The court case would drag out through three years of court motions and delays.

While Rasdall admits her guilt publicly, in court she pleaded not guilty to DUI manslaughter, hoping to avoid a prison sentence. The court case would drag out through almost three years of court motions and delays.

After entering a plea, Rasdall was handcuffed, shackled, strip-searched and booked, sent to jail until her parents posted bail.

"I was in this uniform that said 'maximum security inmate,'" she said. "And I was just like, I could be spending 10 or 15 years of my life like this. What happened?"

Click HERE to read part 2 of Jessica Rasdall's story, as she emerges from therapy and begins to speak out publicly about drunken driving.